Thank you, Helen and Svein.

I'm developing an app that, in the future, there may be some modifications to the table.

So, in order to edit a simple field in table I will almost always have to drop all relationships and indexes, make the changes and recreate keys and relations again?

Regards, Mauro.

--- In firebird-support@yahoogroups.com, Svein Erling Tysvaer <svein.erling.tysvaer@...> wrote:
>
> Make sure you have exclusive access to the table, find the name of the
> primary key using
>
> select rdb$constraint_name
> from rdb$relation_constraints
> where rdb$constraint_type = 'PRIMARY KEY'
> and rdb$relation_name = 'Configuracion'
>
> and then run the following script, only replacing
> <NameThatTheAboveQueryReported>:
>
> ALTER TABLE "Configuracion"
> DROP CONSTRAINT <NameThatTheAboveQueryReported>;
>
> COMMIT;
>
> ALTER TABLE "Configuracion"
> ALTER COLUMN "Item" TYPE VARCHAR(64),
> ADD CONSTRAINT "PK_Configuracion" PRIMARY KEY ("Item");
>
> COMMIT;
>
> As you can see, I've tried to name the primary key - I find it generally
> better to deliberately specify the name than to have to find what name
> Firebird assigns.
>
> HTH,
> Set
>
> Maverick Thunder wrote:
> > Hi, I have a doubt (maybe this was already discussed)
> >
> > I create this simple table in FB 2.1
> >
> > CREATE TABLE "Configuracion" (
> > "Item" VARCHAR(32) NOT NULL,
> > "ValorTexto" VARCHAR(120) NOT NULL,
> > "ValorReal" DOUBLE PRECISION NOT NULL,
> > "ValorEntero" INTEGER NOT NULL
> > );
> >
> > ALTER TABLE "Configuracion"
> > ADD PRIMARY KEY ("Item");
> >
> > when I want to insert some records I notice that one has a longer text for field "Item" so
> > I decided to change the column size from VARCHAR(32) to VARCHAR(64) but the following
> > error arises:
> >
> > SQL Error: unsuccessful metadata update MODIFY RDB$RELATION_FIELDS failed action
> > cancelled by trigger (1) to preserve data integrity Cannot update index segment used by an
> > Integrity Constraint. Error Code: -607. This operation is not defined for system tables.
> > The SQL:
> >
> > ALTER TABLE "Configuracion"
> > ALTER COLUMN "Item" TYPE VARCHAR(64);
> >
> > The table isn't has no relationships with any other and I imagine that the "constraint" is
> > the primary index. Is there a way to modify table columns without errors because, for
> > e.g., converting an INTEGER column to DOUBLE PRECISION gives errors too.
> >
> > To resume, it is almost impossible to make changes to columns, at least, via alter table.
> > How can I circumvent this?
> >
> > Best regards,
> > Mauro H. Leggieri
>